First, you need to identify the codes and standards applicable to the structure in question. I do not know what codes and standards are enforced in Saudi Arabia. it is likely NFPA documents are not applicable.
Second, the NFPA 780 & the other international lightning protection standards do not mandate when a building or structure is to be protected. Some other regulating body such as the building code, local ordinance, or engineered specifications (insurance driven) will detail when a building or structure is to be protected from lightning.
Third, most of the lightning protection standards require an analysis of risk to determine the scale and scope of the lightning protection system to be installed. While building height is a primary component of that analysis, it is not the only factor which determines if and what lightning protection requirements will have to be met.
It would be advisable for you to consult with lightning protection experts familar with the geographical area and the codes and standards applicable to the project...
